Generally speaking, human bone is formed by a hard, thinner cortical outer portion surrounding a softer cancellous inner portion. Conventional bone screws include a threaded shaft for engaging and obtaining purchase in the bone. The bone screw may be manually inserted into the bone by, for example, a screw driver. In use, torque is applied to the bone screw to drive or rotate the screw so that it is inserted into the cortical and cancellous portions of the bone. However, generally speaking, substantially all, if not all, of the bone screw's purchase is achieved via the engagement of the threads with the cortical outer portion. That is, the interaction between the threads and the cancellous inner portion of the human bone add little, if any, purchase as the cancellous inner portion is too soft for threadably engaging the threads of the bone screw.
Thus there exists a need for a new and improved bone fixation element that will take into account the different properties of the human bone in order to increase the purchase strength between the human bone and the bone fixation element.